Visit our Popular Forums

theller · 13-10-2022, 20:57

@Fore and Aft - lets call it art therapy at this point.

Hull sides were straight, with a good form coming out of the original mold, but the pin-holed coating that was on it was the source of the cut down to gelcoat.

I built a tent to give me weather coverage for resealing my deck hardware/hatches/running hardware, and to glass over my toe rail. This is my forever boat. New rig, barrier coat, bottom paint, through hulls.

Goal is sprayed mirror finish quality. I knew what I was getting into - have done automotive finish work and spent a lot of time behind an hvlp gun when I was younger, though... I didn't really grasp the scale factor. woops.

Fun automotive technique on runs... you actually can just spray them out. Literally keep pushing paint on the run until it runs off the bottom. smidge of wet sand work where the run terminates, but hell of a lot easier.

deltaten · 13-10-2022, 23:13

Auto work, huh?
Saw a pro, years back,that ground a bad paint job off. Scored the metal right ugly. Slicked Nitro-Stanover the whole thing and wet sanded till smooth.
I'd say, at this point, that ya might be best off doing the same with a skim coat of Total Boat epoxy filler, guide coat and a long board.

Celestialsailor · 14-10-2022, 07:46

Quote:

Originally Posted by BigBeakie

Firstly, 545 is not a high build primer, it is a finish primer. By the time you would put on a finish primer, your hull is already fair, so.....
Secondly, why would you be "still sanding down to the hull" if the boat is fair?

I think the OP may be confused by such suggestions.

You're right...It's been 30 years since I had used a high build primer. Awlgrip simply calls their high bild primer..."High Build".
Not as many brain cells sine 1990...

Celestialsailor · 14-10-2022, 08:18

Quote:

Originally Posted by deltaten

Auto work, huh?
Saw a pro, years back,that ground a bad paint job off. Scored the metal right ugly. Slicked Nitro-Stanover the whole thing and wet sanded till smooth.
I'd say, at this point, that ya might be best off doing the same with a skim coat of Total Boat epoxy filler, guide coat and a long board.

Brings to mind that song by Zager and Evans..."In the years 2525".

https://www.youtube.com/watch?v=vdSqLfuRN18

skipgundlach · 21-10-2022, 08:24

Two things:

Longboard (hard foam rubber, 2.5" or so wide, with stick-on roll tape)

Dykem (a machinists' high-spot locator) diluted 4-1 with acetone; wipe on when you THINK you have it level, then scuff with longboard. The blank areas are high; either be aggressive with the longboard in that area or take a grinder to it. Rinse, repeat, until the scratches are uniform, and then barrier coat (we like the Sherwin Williams epoxy stuff) and then antifoul (ditto manufacturer)

Pix show original prep first, then some minor touchups on putting on an additional coat, using 60 grit, and a shorter version of the longboards we used (they're available in 36-6 inches in 6 inch increments; we have all of them).

The bottom paint was in stock at the marina, but our first double coat (8 years continuous in the water, first color still working but mostly gone) was the type 45, slower. The last pics is what it looked like after 8 years and after touchup with the type 30 bottom paint, and what a wet ready-for-barrier-coat hull (wash off the sanding dust) looks like...

Icarus · 21-10-2022, 16:33

Quote:

Originally Posted by theller

I had to get really aggressive with removing an old coating from hull sides and deck. Like, 40 grit abranet aggressive. It's time to deal with the expected aftermath. Deep 40 grit scratching.

You might think: "Why the hell did you use 40"... we are 50 hours of sanding into this thing, with 40 grit. It just wasn't happening with 60/80/120. It all had to come off - it was pin-holed, everywhere. Easy on me folks.

Couple options I'm considering.

1. Go super high build on the primer. Sand to my hearts content until I clear the scratches.

2. Get at it again with 80 until I get through the scratches. Afraid I'm going to get real wavy with the surface finish because I'll be hunting the bottom of scratches.

3. Mix putty until my eyes start bleeding and skim coat the whole thing. rough that with 80, then follow up with heavy build primer.

My gut tells me go with a high build primer. Anyone got any practical experience with something this drastic?

Any guidance on how to play it safe? Maybe a small section first, count how many coats I need until I see the scratches fill?

Lay on the hi build primer and keep sanding

I14 · 23-10-2022, 11:38

It really depends on how bad your humps and hollows are rather than the 40 grit scratches in deciding which finishing method is best. If they're bad then you will have to longboard the topsides to ensure your final finish looks mint and that means you need a thick, easily sanded layer to work on. All solvent thinned high build primers are still at best 60% volume solids so will shrink down by 40% as they cure. So it's either multiple coats or you would achieve a better and faster result by toweling or skimming on with a metre long batten an epoxy bog made with microballoons or similar. That will longboard well with 80 grit and you can then work up to 150 grit and then prime, 240 grit sand then topcoat. The bog is close to 100% vol solids so fast and effective as a filler. You need to get a high loading of microballoons, Q-cells or similar low oil requirement filler to ensure easy sanding. Talc is bad as oil requirement is high. I'm assuming it is above the waterline that you are trying to make look pretty, you wouldn't bother below the w/l.